This invention relates to the field of digital event generators, and more particularly to digital event generators that can produce multiple events with variable timing relationships. The term "event" is used here to mean the initiation of a signal having some significance elsewhere in the system, generally for timing and control purposes.
Producing a sequence of digital events with programmable timing relationships to a reference signal is not new. Multiple independent timers or counters can be used to generate a sequence of events with a controllable timing relationship, but this approach is circuitry intensive and is less than optimal in terms of the speeds that can be attained. An approach that reduces the circuitry involved and is capable of faster operation is a circuit consisting of a binary counter and a plurality of digital comparators to monitor the count from the counter and generate the events when particular counts are reached. This approach reduces the total circuitry required and permits the timing of the events to be controlled by selecting different values for the counter output to be compared to. However, the maximum frequency attainable using this approach is limited by the inherent speed limitations of the type of counter used.
What is desired is a circuit that will generate multiple digital event signals, whose timing relationships to a reference signal can be controlled, that will operate at the highest possible speed and yet require a minimum amount of circuitry.